Investigation of beta beta decay in (150)Nd and (148) Nd to the excited states of daughter nuclei
Résumé
Double beta decay of (150)Nd and (148)Nd to the excited states of daughter nuclei have been studied using a 400 cm3 low-background HPGe detector and an external source consisting of 3046 g of natural Nd_2O3 powder. The half-life for the two-neutrino double beta decay of (150)Nd to the excited 0+1 state in (150)Sm is measured to be T1/2=1.33+0.36-0.23(stat)+0.27_-0.13}(syst)] 10.20 y. For other (0v + 2v) transitions to the 2^+_1, ^+_2, 2^+_3, and 0^+_2 levels in ^150Sm, limits are obtained at the level of $\sim (2-8)\cdot 10^{20} y. In the case of ^148Nd only limits for the (0\nu + 2\nu) transitions to the 2^+_1, 0^+_1, and 2^+2 excited states in ^148Sm were obtained and are at the level of \sim (4-8)\cdot 10^20 y.